Lock system for a motor vehicle with multiplexing

ABSTRACT

A vehicle lock system has individual door locks each provided with a printed circuit board on which a microcontroller, motor driver for the lock servomotor, and a multiplexing element are encapsulated, the printed circuit board being mounted in the housing of the respective lock and being connected by the multiplexing element to a single-line data bus for binary communication with the individual lock from the central station.

FIELD OF THE INVENTION

My present invention relates to centralized lock system for a motorvehicle and, more particularly, to a lock system in which at least thedoor locks of an automotive vehicle are connected to a data busutilizing multiplexing.

BACKGROUND OF THE INVENTION

A centralized lock system for an automotive vehicle can have a pluralityof vehicle door locks on the respective doors of the vehicle, a centrallocking unit for controlling the vehicle door locks, a servomotor ineach individual door lock and an electrical control and monitoringcircuit for actuation and monitoring of the central locking unit. Theterm "vehicle door" is intended to encompass also the door of the trunkand/or a hood of the vehicle, as well as the filling compartment door orflap which normally conceals the fitting through which fuel is suppliedto the vehicle.

The door locks can have, aside from the usual functions, like lockingand unlocking, positions providing security against joy riding andvehicle theft. The term "system" is here used in the sense thatencompasses a unit whose components are operated in an integrated mannerfrom a central position.

Door locking systems for vehicles are known in a wide variety ofconstructions as are the door locks which are used therewith. In onelocking system over which the invention is deemed to be an improvement,the control and monitoring circuit for the individual control andmonitoring functions has separate electrical lines running to thecentral station from the individual door locks so that a comparativelylarge number of lines must run to each door lock from the centralstation and be incorporated into the electrical harness of the vehicle.Mounting of the locks and the wiring of them to the harness can be atime-consuming process.

A lock system of the type with which the invention is concerned isfound, for example, in German patent DE 35 26 501 C2 and thecorresponding U.S. Pat. No. 4,735,447.

It should be noted that electrical systems with reduced wiring needsutilizing binary busses, multiplexing and the like are described inGerman patent DE 34 17 956 C2 and German open application DE 41 41 504A1. However the principles of these latter systems have not, to myknowledge, been hitherto utilized in the field of vehicle lock systems.

OBJECTS OF THE INVENTION

It is, therefore, the principal object of the present invention toprovide a centralized lock system for an automotive vehicle which has asimplified electrical construction or wiring without loss ofreliability.

Another object of this invention is to provide a centralized lock systemwhich is reliable, economical and easy to install, and more readilyinstallable in vehicles having a number of doors to be operated by thelock system.

Still another object of this invention is to provide an improved locksystem free from the drawbacks of earlier lock systems.

SUMMARY OF THE INVENTION

These objects and others are attained, in accordance with the invention,in a centralized lock system for an automotive vehicle having aplurality of doors. That lock system comprises:

a respective vehicle door lock at each door of the vehicle, each of thedoor locks comprising:

a lock housing,

an electric servomotor in the housing,

a lock mechanism in the housing operatively connected to the electricservomotor for locking and unlocking a respective one of the doors inresponse to electrical commands fed to the respective lock,

a printed circuit board in the housing provided with dust and moistureexcluding encapsulation,

a microcontroller encapsulated on the printed circuit board and a drivercircuit connected to the microcontroller and encapsulated on the printedcircuit board and responsive to the commands for controlling theservomotor,

at least one control sensor in the housing for monitoring lock operationand producing sensor signals indicating the lock operation, and

a bidirectional multiplexing element encapsulated on the printed circuitboard and connected to the microcontroller for receiving binary signalsand producing the commands therefrom and for receiving the sensorsignals and generating binary signals therefrom;

a bus system interconnecting all of the multiplexing elements fortransmission of binary signals to and receipt of binary signals from themultiplexing elements; and

a central control and monitoring circuit connected to the bus system foroperating the locks in accordance with information applied to the bussystem in the form of binary signals.

More specifically, a vehicle door lock is provided on each of theautomotive vehicle doors, a central locking unit is provided for thedoor locks, the door locks each have electrical servomotors and acontrol and relating circuit is provided for actuation and monitoring ofthe central locking device, operating with control information andmonitoring information.

According to the invention:

1.1 the control and resolution circuit includes a bus system forinformation transfer,

1.2 the bus system operates with multiplex system elements at least oneof which is provided in each of the individual vehicle door locks,

1.3 for monitoring and control each door lock has a microcontroller, amotor driver and a control sensor which is received in the individualdoor lock and is advantageously provided behind the respective multiplexsystem element,

1.4 the multiplex system element, the microcontroller and the motordriver of each door lock is provided on a common printed circuit boardwhich is received in the door lock, i.e. within the housing thereof, and

1.5 the printed circuit board is encapsulated with the elementsdescribed against dust and moisture, i.e. the printed circuit board, themicrocontroller, the motor driver and the multiplexing element areenclosed in a dust-free and moisture-tight hermetic manner in theencapsulation.

The bus according to the invention can provide a single-data line forthe signals transmitted to and from each motorized door lock forcarrying the information for operating that door lock. The bus combinesthe individual components of the information processing system. Onenormally can distinguish between a data bus, an address bus and acontrol bus, in that a data bus serves for the exchange of data, forexample, measurement data, the address bus and control bus serve for thetransfer of control signals and acknowledgment signals. A bus,therefore, is characterized in that all components connected to the bus,by contrast with classical wiring or cable of electrical and electroniccomponents in a point to point manner, acts generally bidirectionally sothat digital signals will be transmitted in each direction.

In the case of a digital bus, the active elements like the locks willhave a two-way data traffic on the bus, providing data signals forgenerating the commands and receiving acknowledgment signals or controlsignals transmitting to the central location details as to the status ofthe individual locks.

An advantage of a bus system is that the components connected theretocan themselves be flexible. The effectiveness of a bus system isstrongly dependent upon the data transfer speed. When a plurality ofactive elements are connected to the bus, prioritizing of theeffectiveness of such elements may be necessary.

A bus system is a system of bus lines which are defined in accordancewith the number and function of the components. A bus system can be asingle strand system in which a single wire may run to themicroprocessor of each particular station or device which can beconnected in a local network. The communication or control informationis exchanged in a multiplex operation. In a multiplexing system, theinputs to the multiplexing device are scanned in succession and theinformation is ordered in a time sequence and applied to thetransmission line and/or information from a transmission line, anddepending upon its order of receipt is delivered to respective outputsof a multiplexing unit. In the receiver, therefore, simultaneous andsynchronous receipt of the signals can allow their distribution to theproper outputs and a bidirectional multiplexing circuit can scan theinput channels and bundle the data for synchronous transmission and canreceive synchronous data and distribute the data to the various outputswhich can be switches or modulators. The inputs can be from varioussensors.

The input channels can have respective addresses facilitating bundlingof the data and the address-carrying signals, e.g. in binary form, canbe bundled for transmission by the multiplexer to a binary data bus fordecoding at another location along the bus in an address decoder whichseparates the address signals, delivering the outputs to respectiveoutput channels and separating the address or label from the data.

The invention is based upon the fact that wiring for a motor vehiclelock system can be greatly simplified without loss of reliability if theelectrical control and monitoring for each lock, instead of beingeffected via respective conductors, is accomplished through the use of amultiplexing unit at each lock and with the aid of a binary bus linkingall of the locks with the central unit. When a printed circuit boardcarrying the essential elements is encapsulated and provided in eachlock housing, the electronic components are protected againstenvironmental influences. The system can provide commands for locking,unlocking, additionally securing the individual vehicle locks againstjoy rides or thefts, releasing the additional locking capacity andproviding mechanical or electronic key operation or switching, all withbinary signals transmitted along a bus without requiring separate linesfor the individual locks.

Most advantageously, the bus system is a digitally operating single-wirebus system with pulse width modulated bits.

In a preferred embodiment of the invention, suitable for use with mostlocking systems, for motor vehicles, the multiplex system elementsutilized at each lock can each have three inputs (bus input, energyinput, ground) and, depending upon the internal circuitry of the doorlock, a number of outputs (for example, for a central lock switch, aninternal lock switch, a key operating switch, control sensors). Ingeneral eight outputs, three for the addresses and five for differentfunctions are suitable. The control sensors which are used to signallock status to the central station can be Hall-effect sensors, i.e.contactless sensors. The printed circuit board, as noted, isincorporated in the housing and is additionally provided with adust-tight and moisture-tight (hermetic) capsule from which anyconductors emerge through correspondingly dust and moisture-tight seals.

When the lock system operates with closed housing locks of the typedescribed in German patent DE 35 26 501 C2, only the outer actuatinglever, an inner actuating rod, an internal safety rod and the electricalcable connection need be provided.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become morereadily apparent from the following description, reference being made tothe accompanying drawing in which:

FIG. 1 is a diagram of a lock system according to the invention;

FIG. 2 is a view of one of the door locks of this system with a portionof the housing broken away to show internal parts;

FIG. 2A is a detail of the region IIA of FIG. 2; and

FIG. 3 is a view of a printed circuit board showing its components inblock diagram form.

SPECIFIC DESCRIPTION

The door lock system shown in FIG. 1 is provided on an automotivevehicle and can comprise a door lock 1 for the driver's door, a doorlock 2 for the front passenger door and door locks 3 and 4 for rearpassenger doors.

The fuel tank fitting can be provided with a flap which can have asimilar lock. The locks 1-4 each include a locking mechanism 5 driven byan electric servomotor 6 of the respective mechanism. In addition, anelectric control and monitoring of the lock from a central location andwhich is capable of processing the information for operation of the lockand monitoring information derived from the locks 1-4.

In the diagram of FIG. 1 it will be clear that operating commands, forexample, locking, unlocking, joy ride or theft prevention can beswitched on or released by an electronic key represented at 8 andcomprising a transmitter 8a and a receiver 8b operating by highfrequency or infrared or through some other electronic wirelessarrangement.

From FIG. 1 it will be apparent further that the central station 7includes a central unit 9 which processes the commands and converts theminto binary information which is bidirectionally transmitted on a bussystem.

The bus system is a single-wire bus in the embodiment shown, comprisingsingle wires 10 running to the door locks 1-4. The bus system 9, 10operates with multiplex system elements 11, one of which is provided ineach of the locking mechanisms 5. As can be seen from FIG. 2, amultiplexing element 11 is provided on the circuit board built into thelock housing. The circuit board components are seen as well in FIG. 3and FIG. 2A shows the multiple inputs and outputs of the multiplexelement 11.

FIG. 3, for example, shows that on the printed circuit board 15 providedwith hermetic encapsulation 20, there is a microcontroller 12 and motordriver 13, the latter being connected to the electric motor 21. Controlsensors 14 can be provided to monitor operation of the lock and thecircuitry 12-14 is provided downstream of the multiplexing systemelement 11 for the respective door and door lock.

A comparison of FIG. 2 and 3 will show that the multiplex system element11, the microcontroller 12 and the motor driver 13 of each door lock 1-4are provided on a common printed circuit board 15 which is incorporatedin the housing of the door lock mechanism 5. Each door is also fullyencapsulated against dust and moisture penetration.

As has been indicated in FIG. 1, the bus system 9, 10 is provided as adigitally-operating single conductor bus system with pulse widthmodulation of the bits.

The multiplex element 11 has three inputs 16, namely, a bus input, anenergy input and ground. The multiplex system element 11 can have anumber of outputs, depending upon the internal configuration, for thecentral lock switch, an internal lock switch for key actuation switchesand for the control sensors. As shown in FIG. 2A, eight outputs 17 canbe provided, three for the addresses and five for the assorted numeraldata and different functions.

The control sensors 14 represented in FIGS. 2 and 3 are contactlesselectronic switches. The printed circuit board 15 has been representedas having a moisture and humidity blocking unit as represented at 18.

In this embodiment, the housing 19 of the lock is fully sealed exceptfor the external actuating lever. The internal rods and the cableconnection, all of which connect through the housing to the interiormechanism 22. The motor 21 has also been shown only diagrammatically inFIG. 2. The closed housing system of FIG. 2 can embody the structure ofGerman Patent 35 26 501 C2 and the printed circuit board is then fullyenclosed in the housing 19 and additionally protected therein.

I claim:
 1. A centralized lock system for an automotive vehicle having aplurality of doors, said lock system comprising:a respective vehicledoor lock at each door of the vehicle, each of said door lockscomprising:a lock housing individual to the respective door locks, anelectric servomotor in said housing, a lock mechanism in said housingoperatively connected to said electric servomotor for locking andunlocking a respective one of said doors in response to electricalcommands fed to the respective lock, a printed circuit board in saidhousing provided with dust and moisture excluding encapsulation, amicrocontroller individual to the respective door lock encapsulated onsaid printed circuit board and a driver circuit connected to saidmicrocontroller and encapsulated on said printed circuit board andresponsive to said commands for controlling said servomotor, at leastone control sensor in said housing for monitoring lock operation andproducing sensor signals indicating said lock operation, and abidirectional multiplexing element individual to the respective doorlock encapsulated on said printed circuit board and connected to saidmicrocontroller for receiving binary signals and producing said commandstherefrom and for receiving said sensor signals and generating binarysignals therefrom; a bus system interconnecting all of said multiplexingelements for transmission of binary signals to and receipt of binarysignals from said multiplexing elements; and a central control andmonitoring circuit having a central multiplexer and responsive to thecontrol sensors of the locks connected to said bus system for operatingsaid locks in accordance with information applied to said bus system inthe form of binary signals.
 2. The centralized lock system defined inclaim 1 wherein said bus system is a single-wire bus operating withpulse-width-modulated bits.
 3. The centralized lock system defined inclaim 1 wherein said multiplexing element has three inputs including abus input, a power input and a ground, and a plurality of outputs. 4.The centralized lock system defined in claim 1 wherein said controlsensor is a contactless sensor.
 5. The centralized lock system definedin claim 4 wherein said contactless sensor is a Hall-effect sensor. 6.The centralized lock system defined in claim 1 wherein the encapsulationis a dust-tight and moisture-tight housing surrounding said printedcircuit board.
 7. The centralized lock system defined in claim 1 whereinsaid lock housing is a closed housing having a connector for an electriccable, an interior actuating rod, an interior locking bar and anexternal actuating lever as exclusive members affording access to aninterior of said housing, said printed circuit board being fullyenclosed in said housing.